In research carried out in a number of Brazilian laboratories, a multidisciplinary scientific team developed a magnetic, luminescent nanomaterial capable of chemically binding to molecules of interest, such as drugs or proteins. This nanomaterial also showed low toxicity in tests with living organisms. With this set of characteristics, the new material can be seen as a multifunctional nanoplatform that is promising for the development of various applications, especially in the areas of biotechnology, health and environment. The study was reported in an article published in ACS Applied Nano Materials (American Chemical Society journal released in 2018), and featured on the cover of the June issue of the journal.
The properties of this nanoplatform derive from the presence of several compounds and elements with distinct properties: iron oxide (Fe3O4, known as magnetite) nanoparticles responsible for magnetism; lanthanide element ions (Gd3 +, Ce3 + and Tb3 +, known as rare earths) responsible for luminescence or light emission, and chitosan (biopolymer obtained from the crustacean exoskeleton), essential for providing chemical bonds of the nanoplatform surface to the external molecules of interest.
The nanoplatform was developed at the Brazilian National Nanotechnology Laboratory of the National Center for Energy and Materials Research (LNNano – CNPEM). The process used for its synthesis comprises a series of steps. Initially, the iron oxide nanoparticles that form the core of the nanoplatforms are synthesized and coated with silicon dioxide (SiO2). Then the luminescent elements and chitosan are incorporated into the nanoparticles forming an outer layer. The result is nanoplatforms of approximately 170 nm in diameter (on average), called Fe3O4@SiO2/GdOF:xCe3+,yTb3+.
To study the magnetic and luminescent properties of the nanoplatform and to characterize its structure and morphology, research groups from the State University of Campinas (Unicamp) and the University of São Paulo (USP) participated in the study.
In addition, the main authors of the paper decided to evaluate the toxicity of nanoplatforms with relation to living organisms – a key step when thinking about health or environmental applications, and they decided to conduct a well-established in vivo test, in which zebrafish embryos (scientific name Danio rerio) are exposed to the material whose toxicity is to be evaluated. These freshwater fish, in fact, has a high genetic similarity to humans (about 70%) and at the same time is cheaper and easier to study than mice or rats, among other advantages.
In the toxicity test, a few dozen freshly fertilized zebrafish eggs were placed in aqueous medium containing the nanoplatforms at various concentrations. The embryos were examined at different development stages using an optical microscope to check for mortality, malformation, edema or changes in size. Tests included embryos with and without chorion (membrane that protects the embryo in the early stages of development). The test results carried out at LNNano showed that nanoplatforms, even at high concentrations (100 mg/L), have low toxicity for all embryo groups.
“This work brings an unprecedented contribution that involves evaluating the toxicity of hybrid nanomaterials using the zebrafish model, a promising alternative method in nanotoxicology, and the influence of the chorion,” says Diego Stéfani Teodoro Martinez, CNPEM researcher at LNNano and one of the corresponding authors of the article.
The embryos were also analyzed at the Brazilian National Synchrotron Light Laboratory (LNLS – CNPEM) to verify the distribution and concentration of nanoplatforms in the organism of the embryos. To do this, the scientists used the synchrotron light X-ray fluorescence microscopy (SXRF) technique, which can accurately map certain chemical elements in biological systems. This technique is available at one of the LNLS experimental stations, coordinated by the researcher Carlos Alberto Pérez, who is one of the corresponding authors of the article.
SXRF analysis showed that nanoplatforms had accumulated in the embryos as a function of exposure time, with higher concentrations in the gastrointestinal tract in the case of already developed mouth embryos – a result that may be significant, for example in the context of healthcare applications involving oral nanoplatform ingestion.
The study was carried out in the context of a postdoctoral project by fellow Latif Ullah Khan, also corresponding author of the article. The completion of the project, says Martinez, was made possible by the availability of skills and facilities at CNPEM’s multi-user laboratories. However, partnerships with other laboratories were also crucial, adds the CNPEM researcher. Professor Marcelo Knobel’s group performed the magnetometry studies at Unicamp. The groups of professors Hermi Felinto Brito and Magnus Gidlund carried out the luminescence and functionalization studies at USP. Finally, Professor Diego Muraca (Unicamp) and researcher Jefferson Bettini (CNPEM) contributed to the structural and morphological characterization using transmission electron microscopy techniques.
“This article was the result of integrating the experience of different Brazilian groups; an interdisciplinary study on the frontier of knowledge in nanobiotechnology and nanotoxicology,” says Martinez, adding that one of the main challenges of the work was integrating knowledge and techniques from different areas, such as Materials, Biology and Toxicology, a task that was coordinated by Martinez and Pérez.
The study received financial support from Brazilian agencies CAPES (including through the CAPES-CNPEM agreement), FAPESP and CNPq (including through INCT-Inomat); from the Brazilian Ministry of Science, Technology, Innovations and Communications (MCTIC) through SisNANO, and The World Academy of Sciences for advancement of science in developing countries (TWAS). The study also received financial support from the Brazil-China Nanotechnology Research and Innovation Center (CBC-Nano).
Applications: biotechnology, health and the environment
According to Martínez, the nanoplatform developed opens perspectives for applications in biotechnology, health and the environment, such as biological tissue and cell imaging systems, medical diagnostic kits, and environmental systems for pollutant detection and remediation
The applications would take advantage of the interesting set of nanoplatform properties. Because they are magnetic, using an external magnet, nanoplatforms could be directed and retained in a particular biological tissue or isolated from, for example, contaminated blood or water. In addition, the luminescence of the nanomaterial would allow visualizing the nanoplatforms within the biological tissues and cells of interest. Finally, the presence of chitosan would enable the chemical binding of drugs and other molecules that would serve for the diagnosis and/or treatment of diseases. “However, much study is still needed for real applications and commercialization of this nanoplatform, as it is a new material and needs to be tested on different models in the future,” says Martinez Martinez.
[Paper: Fe3O4@SiO2 Nanoparticles Concurrently Coated with Chitosan and GdOF:Ce3+,Tb3+ Luminophore for Bioimaging: Toxicity Evaluation in the Zebrafish Model. Latif U. Khan, Gabriela H. da Silva, Aline M. Z. de Medeiros, Zahid U. Khan, Magnus Gidlund, Hermi F. Brito, Oscar Moscoso-Londoño, Diego Muraca, Marcelo Knobel, Carlos A. Pérez, Diego Stéfani T. Martinez. ACS Appl. Nano Mater. 2019, 2,6, 3414-3425. https://doi.org/10.1021/acsanm.9b00339.]
Fascinated by science since he was a child, with a representative at his home (his father, a renowned neuroscientist), Carlos Frederico Oliveira Graeff, born at Ribeirao Preto (state of São Paulo), chose the area of Physics as his university studies. He obtained his bachelor’s (1989), master (1991) and doctor (1994) degrees in Physics from the University of Campinas (Unicamp). During his master’s and doctorate program, supervised by professor Ivan Chambouleyron, he took his first steps as a researcher in the Materials area with studies on materials based on germanium and silicon. During his doctorate he participated in a research internship at the Max Plank Institut für Festkörperforschung in Germany.
He returned to Germany in 1994 until 1996 for a postdoctoral period to work on electronic magnetic resonance, semiconductors and electronic devices at the Walter Schottky Institute of the Technische Universität München (TUM), with a grant from the German foundation Alexander Von Humboldt.
Upon returning to Brazil, he became a professor at the Department of Physics and Mathematics of the University of São Paulo (USP), where he remained for 10 years. In 2006, he joined the Faculty of Sciences of Bauru at the State University of São Paulo (UNESP) as a full professor, where he is still teaching and researching. Throughout his academic career, Graeff has been visiting professor or researcher at several institutions in France, China and Switzerland.
From 2007 to 2009, Graeff was coordinator of the Post-Graduate Program in Materials Science and Technology (POSMAT) at UNESP – Bauru campus. Between 2009 and 2014, he was the coordinator of the newly created Materials Area of CAPES, responsible for the evaluation of Brazilian post-graduate programs in Materials, among other functions. From 2011 to 2013, Graeff was president of the Humboldt Club of Brazil and in 2012 and 2013 he was scientific director of B-MRS. The scientist also fulfilled or performs management or advisory functions at Brazilian agencies FAPESP and CAPES, and at IUPAC (International Union of Pure and Applied Chemistry).
In 2017, after having participated in the editorial board of several international journals, he was appointed associate editor in the photovoltaic area of the journal Solar Energy (impact factor 4,018), of Elsevier publishing house. Also in 2017, he became Dean of Research at UNESP, a post he holds until now.
With an h index of 28, Graeff is the author of about 200 indexed papers that have more than 2,500 citations, according to Google Scholar. In three decades of scientific work, together with his team at the Laboratory of New Materials and Devices at UNESP and his numerous national and international collaborators, Graeff has contributed to the field of materials research with multiple subjects. Among his most cited articles there are studies on synthetic diamond, silicon and germanium heterostructures, conjugated polymers, latex and melanin (biological material with semiconductor properties that are promising for the development of bioelectronic devices).
The researcher has also worked in the area of photovoltaic energy (direct conversion of solar radiation into electricity), with numerous contributions to the development of solar cells based on different materials (dyes, perovskites and organic semiconductors). On this subject of photovoltaic energy, Carlos Graeff will offer a plenary lecture at the XVII B-MRS Meeting, to be held in Natal (RN) from September 16 to 20.
The following is an interview with this outstanding researcher of our community.
B-MRS Newsletter: How or why did you become a scientist? Did you always want to be a scientist? Also, briefly tell us what led you to work in the field of materials.
Carlos Graeff: My father, Frederico Graeff, is a well-known researcher and perhaps one of the most important influences in my decision. My aunts were also teachers and researchers, so from an early age I had access to the world of science from my home, which has always fascinated me. The decision to study physics was largely due to the various books I read and from the television Cosmos series presented by Carl Sagan. The decision to work in the Materials area came later on during my baccalaureate in physics after the first courses in condensed matter physics and semiconductors. From the beginning of the graduate studies I worked in materials, and soon I was attracted by the interfaces of physics with chemistry and biology in very different subjects of materials science and engineering.
B-MRS Newsletter: What do you believe are your main contributions to the Materials area? Please consider all aspects of scientific activity.
Carlos Graeff: It is always difficult to choose key contributions. In my case in particular it is easy to see, reading my CV, a very eclectic trajectory in terms of studied materials and applications. Using originality as a preference, I will dwell on three themes; the first is the production of CoS (cobalt sulfide) the basis of ecological paints for the production of electrodes for solar cells. We have achieved a simple, industrial and ecological method to replace platinum in dye-based solar cells. In the second theme, we have proposed several alternative methods for the synthesis of melanin, the material involved in tanning, and with this we have been able to produce biocompatible materials with very special characteristics with regard to, for example, solubility. We are identifying a very important defect for this material using, as a main tool, computational simulations combined with spectroscopic techniques. We are sure this material will be important in the emerging area of bioelectronics. In the third theme, we describe in detail the whole degradation process of organic semiconductors, identifying routes for the production of high sensitivity dosimeters for applications in hospitals and clinics that use, for example, gamma rays for cancer treatments and diagnosis. We also have had very unique contributions in the physics of electrically detected magnetic resonance, increasing the sensitivity and the general understanding of the physical phenomena involved. In addition to these fundamental contributions, I was responsible, proudly and with satisfaction, for the implementation of the materials area at CAPES. Another source of satisfaction regards the good students I was fortunate enough to mentor, many of them brilliant scientists. I helped and coordinated the assemblage of several laboratories both here in Brazil and abroad, most recently I helped set up a magnetic resonance laboratory in China.
B-MRS Newsletter: Now we invite you to leave a message for our readers who are starting their scientific careers.
Carlos Graeff: I started my master’s degree in 1989, a time that was perhaps as troubled as the current one, do not get discouraged! With focus and a bit of luck it is always possible to create new ideas, build a solid career and contribute to our beautiful country. We are going through a great revolution, with the emergence of new technologies that will profoundly transform society. Intelligence will increasingly play a decisive role in the direction of our society, be prepared to work in this new world of great opportunities. Always seek out dialogue with specialists from the most different areas of knowledge and from various countries. Quite possibly, in the coming years we will unravel the mysteries of how the brain works, we will master limitless forms of energy and ecological production, generate artificial intelligence. Open up to what is new, be bold, Brazil needs your citizen and entrepreneurial spirit.
B-MRS Newsletter: You will deliver a plenary lecture at the XVII B-MRS Meeting. Leave an invitation to our community.
Carlos Graeff: Photovoltaic energy is reaching its commercial maturity, we are living an unprecedented energy revolution. In the lecture I will show some updated data on the perspectives of using photovoltaic cells in Brazil and in the world; its principles of operation; the challenges for scientists and material engineers in this relentless race for increasingly efficient, durable and environmentally friendly materials, processes and devices. I will present our group’s latest results on this topic.
Since April of this year, the Brazilian Nanotechnology National Laboratory (LNNano) of the National Center for Research in Energy and Materials (CNPEM) is headed by the scientist Adalberto Fazzio, 66, born in the São Paulo state city of Sorocaba.
Adalberto Fazzio has been studying materials through computational tools for over four decades. He pioneered in Brazil the use of ab initio calculations, widely used in the study of materials properties, and made significant contributions toward understanding transition metals, amorphous systems, gold (Au) and silver (Ag) thin films, carbon nanostructures, silicon, topological insulators, and other materials. Fazzio and his research group, known as SAMPA (acronym for “Simulations Applied to Atomic Materials and Properties”), have successfully worked on this at the Institute of Physics of the University of São Paulo (USP) and also with several theoretical and experimental collaborators from Brazil and abroad.
Adalberto Fazzio received his undergraduate (1972) and master’s degree (1975) in Physics at the University of Brasília (UnB) and his doctorate (1978),also in Physics, at USP.
Fazzio became a professor at the Institute of Physics – USP in 1979, shortly after completing his doctorate. In 1985 he became an associate professor at that university and in 1991 he became full professor. He was a visiting researcher at the National Renewable Energy Laboratory (USA) from 1983 to 1984 and at the Fritz-Haber-Institut der Max-Planck-Gesellschaft (Germany) from 1989 to 1990. In May 2015, he retired from USP. He was a visiting Professor at the Brazilian Federal University of ABC (UFABC) in 2016.
Throughout his career, Fazzio has held several management positions, such as president of the Brazilian Society of Physics (SBF) from 2003 to 2007; pro tempore president of UFABC from 2008 to 2010; micro and nanotechnologies general coordinator at the Ministry of Science, Technology and Innovation (MCTI) in 2011; assistant secretary of the Technology, Development and Innovation Secretariat of MCTI from 2011 to 2013, and director of the Institute of Physics – USP from 2014 to 2015.
He has also received other honors, such as the Brazilian National Order of Scientific Merit in 2006 (promoted to the Grand-Cross class in 2010). In 2013 he was elected a fellow of TWAS (The World Academy of Sciences). He is a member of several scientific societies, such as the Brazilian Academy of Sciences and the Academy of Sciences of the State of São Paulo in Brazil, and the American Physical Society, American Chemical Society and Materials Research Society in the United States.
Fazzio is the author of over 270 articles published in indexed scientific journals. His scientific production has about 8,000 citations, according to Google Scholar. He has supervised approximately 40 master’s and doctoral students.
Here is an interview with the scientist.
SBPMat Bulletin: Tell us what led you to become a scientist and in particular to work in the area of Condensed Matter Physics.
Adalberto Fazzio: When I finished my Physics course at the University of Brasilia in 1972, I met Professor José David Mangueira Vianna, who had returned from Switzerland with many projects on Molecular Physics. At that time we were talking about quantum chemistry. He presented a master’s project that was an improvement on semi-empirical models based on the Hartree-Fock method. Due to the low computational capacity of that time, these methods originating from the ZDO (Zero Differential Overlap) approximation were the most widely used to shed light on the electronic properties of molecules. After my master’s degree, I went to the Institute of Physics – USP in the group of Professors Guimarães Ferreira and José Roberto Leite (my doctoral advisor), changing from molecules to solids and from Hartree-Fock to DFT (Density Functional Theory). At that moment I became a Condensed Matter Physicist in a Department of Physics of Materials created by Professor Mário Schemberg. My thesis was about deep level impurities in semiconductors. Bear in mind this was in 1976 and the question was how to treat a crystal that has lost its translational symmetry. Finally, I developed a model, “Molecular Cluster Model for Impurities in Covalent Semiconductors.”
SBPMat Bulletin: What do you believe are your main contributions to the Materials area? We would like to ask you to go beyond listing the results and to briefly describe the contributions you consider as the most relevant. In your response, we ask that you consider all aspects of scientific activity. Feel free to share references to articles and books, if relevant.
Adalberto Fazzio: Whenever we reflect on the main contributions in a given area, we look at the most cited articles, which do not always correspond to the articles that the authors would expect to be the most cited. But I will try to give you a brief description of some of the themes in which I believe I made a contribution that was highlighted. In the study of defects and impurities in semiconductors, I highlight the study of transition metals (TM) in semiconductors. At the time – until 1984 – there was a wealth of experimental data concerning the position of levels of impurities in the gap and the optical excitations of all MT-3ds. And the theoretical calculations based on a medium-field theory did not explain these data. During my post doctoral research at NREL (National Renewable Energy Laboratory) in 1983/84, we developed a model to describe the experimental data. It was a model that coupled the field crystal theory with the DFT theory, which described effects of multiplets from the TM impurities. Several articles were published applying this model. The model is presented in detail in Phys. Rev. B 30, 3430 (84). This work was in collaboration with the researchers Alex Zunger and Marilia Caldas. And those results led to a letter in the Appl. Phys. Lett. (1984) which would be of great interest to experimental physicists, titled “A Universal trend in the binding energies of deep impurities in semiconductors”. A major change occurred in this area in the late 1980s, with the “Large Unit Cell” calculations, DFT method and pseudo potentials. Today known simply as “ab initio methods” or “free parameters”. Regarding this development, I was at the Max Planck Institute in Berlin, working with Matthias Scheffler. Together with my doctoral students (T. Schmidt and P. Venezuela), we were pioneers in the use of this type of methodology in Brazil, widely used until now. After these studies, I started working with amorphous systems. Since we could now work with systems containing many atoms per unit cell, we decided to couple the ab initio calculations using structures generated by Monte Carlo simulations. I highlight two papers: one in a-SiN (PRB, 58, 8323 (1998)) and a-Ge:N (PRL 77, 546 (96)).
At the end of the 1990s, at the Brazilian National Synchrotron Light Laboratory (LNLS), Professor Daniel Ugarte was performing beautiful experiments with HTEM, where he observed the formation of linear chains of atoms in Au and Ag fine films. Our group at USP, in cooperation with Edison Zacarias at UNICAMP, had begun studies to understand the formation of linear chains of Au atoms. Some of the questions were about how these chains broke and how we could explain the great distances that appeared between atoms. This experiment-theory interaction was a very important moment. Several papers were published, one which was widely cited “How do gold nanowire break?” (PRL 87, 196803 (2001)). This work was the cover of PRL and highlighted by the editor of Science. And later we showed how oxygen acts to trap the Au atoms in the wires (PRL 96, 01604 (2006)) and the effects of temperature and quantum effects on wire breakage and stability, important aspects to understand the observations (PRL 100, 0561049 (2008)).
In the same period, our group at USP focused on the study of nanostructures of carbon, silicon, etc. Although we had strong tools for describing electronic, magnetic, optical and mechanical properties, the understanding of these materials lacked the properties of electronic transport. In this context, we developed a computational code based on the Landauer-Büttiker theory. Several PhD students were involved in this code, which is known as TRANSAMPA. And, in my opinion, several important works were carried out to better understand the behavior of electronic transport properties. To exemplify this, we were pioneers in describing the transport in doped graphene tapes (PRL 98,196803 (2007)). I should also mention the collaboration with Professor Alexandre Reilly from IFT (Institute of Theoretical Physics of UNESP) who was then a post-doc, which resulted in a very important improvement of this code, and which allowed to treat materials with the realistic dimensions used in the experiments. In 2008, in a paper titled “Designing Real Nanotube-based Gas Sensor” (PRL 100, 176803), we showed how nanotubes can function as realistic-sized sensors, with defects. Using first-principle calculations, we had systems of micrometric dimensions within our reach.
Currently, my research is more focused on the search for devices formed by 2D materials whose interface is primarily built by van der Waals interactions. For example, like graphene, a new 2D material was isolated from exfoliated black phosphorus, also called phosphorene. We studied the graphene/phosphorene interface (PRL 114, 066803(20015)), showing how a device can be constructed.
Another class of materials I have been working on concerns the well-known topological insulators. A Topological Insulator (TI) is a material that has no states of energy gap “at the edges” and whose “bulk” is insulating! These states are topologically protected and robust against disturbances. In the case of two-dimensional (2D) materials (2D), they are known as insulators that feature Quantum Spin Hall (QSH). The scattering surface state is protected by time reversal (TR) symmetry, leading to an electronic transport without energy dissipation. In 2011, together with the UFU group, we showed how magnetic impurities in topological insulators have their spin texture modified (PRB 84, 245418 (2011)). Recently, in collaboration with Professor Zhang from the Rensseler Polytecnic Institute, we presented a general model for describing the topological/trivial interface. We showed, for example, the Bi2Se3/GaAs interface. There were replicas of the Dirac cone that emerged from the interface interaction including semiconductor states (Nature Comm. 6, 7630(2015)). Phosphorene is a 2D material that has semiconducting properties. In cooperation with the group of Professot Alez Zunger, of the University of Colorado, we studied this material under the action of an electric field and showed that for three or four layers of phosphorene, under the action of the field, it has a topological transition (NanoLett. 15, 1222 (2015)).
Finally, I would like to mention an activity that I am initiating, which is the use of Machine-Learning techniques for material properties. In particular, I have focused on topological insulators. And as I mentioned earlier, specifying the more relevant studies I have left out many others.
As for other types of contributions, together with José Roque I built a very productive group at IF-USP, known as SAMPA (Simulation Applied to Materials – Atomic Properties) where numerous doctors and masters, and several postdocs were cultivated. I should add that all this was possible mainly due to the support of Fapesp, via thematic projects. I was head of the Department of Materials Physics, Director of IFUSP and pro tempore Director of the Federal University of ABC. From a management point of view, I would like to highlight my participation at the Ministry of Science, Technology and Innovation, where I was the Under-Secretary of Setec (Technology and Innovation Secretariat) and SCUP (Secretariat of Research Units). And I am proud to have coordinated the creation of the Brazilian Nanotechnology Initiative, where the SISNANO system is an important arm – a set of laboratories dedicated to technological research and development.
I also wrote two books that have been adopted: “Introduction to Group Theory: applied in molecules and solids”, together with Kazunori Watari and “Quantum Theory of Molecules and Solids”, together with José David Vianna and Sylvio Canuto.
SBPMat Bulletin: You have just taken on the direction of the Brazilian National Nanotechnology Laboratory (LNNano). Please share with the Materials community your plans for LNNano. How do you see the situation of nanoscience and nanotechnology research in Brazil given the recent budget cuts?
Adalberto Fazzio: Two weeks ago I took on the direction of the National Nanotechnology Laboratory (LNNano), one of the four National Laboratories of the National Center for Research in Energy and Materials (CNPEM). This is a laboratory recognized for its excellence, dedicated to the production of knowledge in nanotechnology, moving from basic science to technological innovation.
I was very happy and I hope to continue the work of the researchers who were at the forefront of LNNano and who preceded me, such as Daniel Ugarte, Fernando Galembeck and Marcelo Knobel. This is the laboratory that holds a management bond with MCTIC fully dedicated to nanotechnology. One of its main missions is to service external users through open equipment. An example is the electron microscopy and probes park, which is certainly the best equipped in Latin America. LNNano is the main executor of government policies in the area. We have intense in-house mission-oriented research activity with impact studies. We are currently undertaking minor restructurings to better serve external users and to strengthen ongoing research.
The nanotechnology platform has raised considerable resources in all developed countries of the world. For example, the US government has annually deposited something in the order of US$ 1.8 Bi. Unfortunately, in Brazil we have had difficulties to provide continuity to even much more modest programs. However, the community has responded with great capability to the development of nanotechnology products. Today, for example, anchored in the SISNANO system, we have about 200 companies seeking innovation in the Nano area; and in particular, the performance of LNNano has been outstanding.
What we cannot however, is face budget cuts in science and technology every year. We are in a very delicate moment in our economy, low growth, but it is imperative to preserve the achievements of the last decades in the area of science and technology. The programs in the area of research and technology development must be preserved. This is because when the crisis is over, the country must be prepared to continue growing. Therefore, it is fundamental to continue generating new knowledge, striving for technological innovation and also training qualified human resources. In other words, the economic slowdown should not be accompanied by investment cuts in technology and development research.
SBPMat Bulletin: Please leave a message for the readers who are starting their scientific careers.
Adalberto Fazzio: The greatest wealth in our country is human capital. Brazil has a large young population, young people who are often in the middle of the path in their scientific and technological careers, because they are not able to envision in the future the acknowledgment and respect for a fundamental activity, which is the search for knowledge. Those who desire to pursue a scientific career must persevere and stand firm in their studies.
Angelo Fernando Padilha was born on August 30, 1951 in Novo Horizonte, a small city in the state of São Paulo, Brazil. He attended primary school and the first years of high school in his native city, and when he was 16 years old he moved to São Carlos, some 170 km from Novo Horizonte, to enroll in a “scientific course” that covered the last three years of secondary education and that provided the student a more in depth education than the “classical course” in Mathematics, Physics, Chemistry and Biology.
In 1970, he enrolled in the just created undergraduate course in Materials Engineering at the Federal University of São Carlos (UFSCar). He graduated in 1974. The following year he participated in a specialization in Nuclear Science and Technology of the Brazilian National Nuclear Energy Commission (CNEN), offered at the Institute of Atomic Energy (IEA), currently the Nuclear and Energy Research Institute (IPEN), in the city of Sao Paulo. That same year he began working at IEA with research and development of materials for nuclear reactors. Also in 1975, Padilha began his master’s degree in Metallurgical Engineering at the University of São Paulo (USP), which he concluded in 1977 with the approval of his dissertation on recovery and recrystallization in aluminum alloy.
In 1978, still with the IEA, he began his PhD in Mechanical Engineering at the Universität Karlsruhe, now Karlsruher Institut für Technologie (KIT), Germany, obtaining a Doktor-Ingenieur diploma in 1981 after defending his thesis on precipitation in stainless steel, used in the fuel element of the German fast breeder reactor SNR-300. The following year, at the Max Planck Institut für Metallforschung in Stuttgart, Germany, Padilha participated in a three-month specialization in Materials Science in which he studied phase diagrams involving refractory metals.
From 1984 to 1986, in addition to his research activities at IPEN, he was professor in the undergraduate course in Metallurgical Engineering at the Mackenzie Presbyterian University, also in São Paulo.
From 1987 to 1988, he was a postdoctoral researcher at Ruhr Universität Bochum (RUB) in Germany.
In 1988, after 13 years working at IPEN, Angelo Padilha became a lecturer at the Department of Metallurgical and Materials Engineering at the Polytechnic School of the University of São Paulo (EPUSP). At the Polytechnic he became Adjunct Professor in 1989, and in 1993 he was approved as a Full Professor.
In 1993, he returned to RUB, Germany, for a specialization in duplex stainless steels. In 1998, he held a second postdoctoral fellowship at the University of Wales Swansea, now Swansea University, UK.
From July 2011 to November 2015, USP granted him a leave of absence to hold management positions in agencies linked to the Ministry of Science, Technology and Innovation (MCTI), currently Science, Technology, Innovations and Communications (MCTIC). During this period he was president of CNEN and of its deliberative commission, president of the National Fusion Network – RNF (created in 2006 to coordinate and expand nuclear fusion research in Brazil) and president of the board of directors of two nuclear companies linked to the MCTI , Nuclebras Heavy Equipment (NUCLEP) and Nuclear Industries of Brazil (INB). He was also a member of the sector funds coordination committee and from 2012 to 2014 he was a member of the technical-scientific council of the Brazilian Center for Research on Physics (CBPF).
He is the author of more than 100 papers published in indexed scientific journals and about twenty books and book chapters, such as the well-known in Brazil textbook “Materiais de Engenharia.” His academic work has approximately 2,800 citations, according to Google Scholar. He has supervised 25 master’s dissertations and 24 doctoral theses.
Throughout his professional career, Padilha received several awards from the Presidency of the Republic, the Brazilian Navy and the Brazilian Association of Metallurgy and Materials (ABM), among other entities.
Currently, Angelo Padilha is a full professor at EPUSP where he teaches undergraduate and graduate courses and carries out research on metals. He has been a full member of the Academy of Sciences of the State of São Paulo since 2012 and a senior level CNPq productivity grant holder (level awarded to active scientists in research and teaching of human resources who have been 1 A or B level for a minimum of 15 years). His h index is 27, according to Google Scholar.
Our interview with the researcher.
SBPMat Bulletin: Tell us what led you to study materials engineering in the first group of Materials Engineering in Latin America (UFSCar, 1970-1974) and then become a researcher in the field.
Angelo F. Padilha: I had already decided to be an engineer while in high school, but I was not sure about which engineering modality I would choose. After completing high school in my hometown (Novo Horizonte, SP), I went to São Carlos to begin the scientific course. São Carlos was fundamental for my academic background. The city offered everything a 16-year-old boy could wish for! In the student environment there was plenty of culture, debate and rebelliousness. I’m talking about the beginning of 1967. The worst period of the military regime that had started in 1964 was yet to come.
My aunt told me about the creation of a materials engineering course in São Carlos after reading an article or an interview by Professor Sérgio Mascarenhas in the city newspaper, which made an impression. It was the first time I had heard of this Engineering modality. The entrance examination aroused my curiosity as it was very different from the exams of that time. I did very well and later I enrolled. The first group of materials engineering at UFSCar consisted of 50 students: 2 girls and 48 boys. The university had been installed on a farm of more than 200 acres, not far from the city, and the initial facilities were adapted. It was a calm and warm environment. Today, I can better evaluate what that meant and I am convinced that the course as a whole was excellent. The course offered us a consistent and modern scientific basis. The experimental classes were of the highest quality I know of for an engineering course. Thanks to the scientific and technological base acquired during my five years at UFSCar, I was able to take full advantage of the master’s degree in metallurgical engineering at the Polytechnic School and then the PhD at the Faculty of Mechanical Engineering at the University of Karlsruhe. Many students in our class carried out postgraduate studies at top universities in Brazil and abroad.
SBPMat Bulletin: From your perspective, what are your main contributions to the materials field? Please give us a brief description of the contributions you believe had the greatest or most outstanding impacts considering all aspects of your scientific activity.
Angelo F. Padilha: The materials area did a lot more for me than I did for it. I have never worked on the frontier of knowledge, nor have I sought scientific niches. I use modern scientific concepts and advanced experimental techniques to study, understand and perfect traditional and widely used materials such as steels and aluminum alloys. For example, my most read and cited paper (in co-authorship with Paulo Rangel Rios) is a review paper published in 2002, which discusses the microstructure of austenitic stainless steels; a material discovered in 1911 which is still widely used.
I consider writing technical books in Portuguese as a gratifying commitment. I published my first book on techniques of microstructural analysis, in co-authorship with Francisco Ambrózio Filho, in 1985. I am very grateful to see my books distributed throughout several libraries in the country. Although they are all very simple, they are read as well as cited.
I truly enjoy teaching, I have had hundreds, maybe thousands of students and have supervised dozens of students. To this day I am pleased to mentor students and to teach first-year materials science classes at Poli as well as more specific subjects in the final years of undergraduate and graduate studies. I believe the interaction with the industry is fundamental for a professor and researcher in the area of engineering. More than half of the work I did was in cooperation with the industry.
SBPMat Bulletin: Your trajectory in research and management in institutions of the nuclear energy segment is significant. From your perspective, what are the research materials challenges for the nuclear area?
Angelo F. Padilha: My first job as an engineer was in the nuclear area, in the Coordination of Materials Science and Technology (CCTM) of the Institute of Atomic Energy (IEA), now IPEN-CNEN. The group was created and headed by Professor Shigueo Watanabe. It consisted of about 50 people, nearly all solid-state physicists. My interaction with them was an important school for me.
The applications of nuclear technology include not only nuclear power generation, but also numerous applications in industry, medicine, agriculture, in addition to nuclear propulsion. For example, the number of people who have already benefited from the radioactive drugs produced at IPEN is comparable to the number of people who benefit from the electricity generated by the reactors installed in Angra dos Reis.
Almost all materials used in the construction of a nuclear reactor, a nuclear powered submarine, or a centrifuge for enriching uranium isotopes are materials that were not developed for these applications. In the 1950s, when Americans built the first nuclear-power generating reactor and the first nuclear-powered submarine, in terms of materials, they had to primarily develop uranium and zirconium technology. Hundreds of other materials crucial for the aforementioned applications were already available or only needed some adaptation.
On the other hand, nuclear technologies have some particular characteristics: i) they are dominated by few countries; ii) many of them cannot be purchased on the market; iii) there is little international cooperation, especially in sensitive nuclear technologies; iv) they are complex technologies and require a great deal of human and economic resources to be developed; v) they are generally mature technologies, mastered and perfected over decades. By mastering a mature technology a country can quickly turn it into geopolitical or economic advantage.
Over the last sixty years Brazil has built a nuclear program that can be classified as one of the ten or twelve most important on the planet. Additionally, we have large uranium reserves. From a materials point of view, we still depend on imports, which often encounter enormous obstacles. I believe the biggest challenges and opportunities in the area of materials for nuclear applications lie in national production, in adaptations and in improvements. Future innovations are more likely to be incremental than radical.
SBPMat Bulletin: Leave a message for our readers who are initiating their scientific careers.
Angelo F. Padilha: Go after a consistent scientific education, the rest will be a consequence. A researcher with a deep understanding of the fundamental disciplines such as thermodynamics, crystallography and phase transformation will always be welcome in any research group. Do not be discouraged when facing our gargantuan and tangled bureaucracy.
SBPMat Bulletin: Your name appears in the “interdisciplinary materials commission,” created at the end of 2000 to make possible the foundation of SBPMat. Could you share some recollections or comments about your participation in the creation this society?
Angelo F. Padilha: I believe SBPMat was created at the right time and with the right profile. I consider this to be the main reason for its enduring success. Overall, the “Interdisciplinary Materials Commission” contributed in some way; some more than others. I am certainly among the least contributors. I think the articulating ability of Guillermo Solórzano and the scientific leadership of Edgar Zanotto were decisive. I am proud to have participated in the creation of SBPMat.
The Department of Materials Physics and Mechanics of the Physics Institute of the University of São Paulo, Brazil, invites highly-motivated candidates to apply for one permanent position, for a salary of R$ 10.360,07. The opening is for Experimental Condensed-Matter Physicists, at the Assistant Professor level and is part of an initiative for further significant improvement of DFMT’s faculty.
The University of São Paulo has been consistently ranked among the top research institutions in Latin America. DFMT has proven academic excellence, and its faculty members are extremely active in many different topics such as New Materials, Nanoscience, Quantum Devices, Semiconductors, Biomolecular Physics, Organic Semiconductors, Complex Systems, Low-Temperatures Physics, and Magnetism.
New faculty members are expected to teach undergraduate and graduate courses, show research productivity commensurate with their experience, and a capacity to develop and sustain a research program that will result in peer-reviewed publications. They are also expected to advise students, provide service to the university, and sustain international collaborations. The application and the selection process can be done in Portuguese or entirely in English if the candidate does not speak Portuguese. We strongly encourage candidates from Brazil as well as from other countries to apply. The application forms and a description of the documentation necessary to apply can be found in the links Rules and Documentation. We expect the presential interviews to take place in the second semester of 2017 (in order to start the appointment by March 2018).
The Laboratory of Bioelectrochemistry and Interfaces at São Paulo University (USP), campus at São Carlos, São Paulo state, Brazil, invites applications for a postdoctoral research fellowship in bioelectrochemistry under supervision of Professor Frank Crespilho and funded by Foundation for Research Support of the State of São Paulo (FAPESP) contract. The successful candidate will conduct research on the molecular interaction between biomolecules and nanostructures, including:
developing and testing enzymes bioelectrodes;
transferring high activity/selectivity biocatalyst to a surface-confined environment;
studying the interplay between charge transport, mass transport, and molecular conformation of enzymes;
developing new tools for FTIR Chemical Imaging coupled with electrochemistry.
Fellowship for postdoctoral researchers allows you to carry out a long-term research project (12-24 months), starting at 10/2016.
Applicants must have a Ph.D. in chemistry, chemical engineering, electrochemical engineering, or a related field. Experience in enzymes immobilization and basic electrochemistry is required. Experience with UV-Vis spectroscopy, and FTIR spectroscopy, is preferred. The successful candidate must have excellent communication skills and excel in a highly collaborative research environment. In addition to the timely publication of research results in peer-reviewed journals, the responsibilities of the postdoc include drafting progress reports. Interested individuals should send a (i)cover letter, (II) CV and list of publications, and have (III) two letters of recommendation sent to email@example.com. The deadline for application is 09/11/2016.
[Paper: Oxide-cladding aluminum nitride photonic crystal slab: Design and investigation of material dispersion and fabrication induced disorder. Melo, EG; Carvalho, DO; Ferlauto, AS; Alvarado, MA; Carreno, MNP; Alayo, MI. Journal of Applied Physics 119, 023107 (2016). DOI: 10.1063/1.4939773.]
Designing structures to manipulate light
Photonic crystals are nanostructures capable of manipulating visible light and other forms of electromagnetic radiation by organizing its structure in periodic patterns.
In addition to the natural materials with these characteristics, such as opal, photonic crystals are man-made and are generally classified as metamaterials. Its characteristics (shape, size and composition) are designed to control light waves. Through nanofabrication processes these become tangible structures and are used in many “nanophotonic” devices. Nevertheless, producing these structures is by no means a simple task.
With a study based on computer simulations, a team of Brazilian scientists headed by researchers from the Polytechnic School of the University of São Paulo (EPUSP) presented scientific contributions that can be used to improve the production of photonic crystals to enhance their performance of manipulating light. According to Emerson Melo, the first author of a paper on the study that was recently published in the prestigious Journal of Applied Physics (JAP) “the work presents a detailed analysis of the effects caused by nanofabrication processes on the optical properties of planar photonic crystals produced on silicon dioxide-cladding aluminum nitride”.
“The idea emerged from the opportunity of combining the excellent optical and physical characteristics of aluminum nitride (AlN), such as transparency over a wide wavelength range (from the near infrared to the ultraviolet range), its non-linear effects, great stability and temperature variations, with the advantages provided by photonic crystals, such as the construction of high-efficiency waveguides, curves and resonant cavities in nanoscale dimensions, in addition to the various optical effects of photonic crystals, such as very low group velocity and low-intensity nonlinear effects of the materials”, adds Emerson, who is a doctoral student in Microelectronics – Photonics in EPUSP, within the Group of New materials and Devices of the Microelectronics Laboratory of the Department of Electronic Systems Engineering. Emerson`s doctoral research, whose advisor is Professor Marco Isaías Alayo Chávez, enquires into the study, production and characterization of nanophotonic devices such as waveguides, resonant cavities, optical modulators and switches in aluminum nitride photonic crystals.
The study that resulted in the paper published in the JAP began with an experimental stage. Thin films of aluminum nitride and silicon dioxide (SiO2) were manufactured by the EPUSP group, and with the research collaboration from UFMG and UNESP they were analyzed by the Variable Angle Spectroscopic Ellipsometry (VASE) technique to determine the dielectric functions, which was later used as the theoretical research data.
Then, the EPUSP group designed a photonic crystal, ideal in terms of performance and manufacturing possibilities, consisting of a layer of aluminum nitride between two silicon dioxide layers, with round holes arranged in a repeating pattern along the “sandwich” material. Using analytical and numerical methods, the USP researchers simulated some of the “side effects” of the photonic crystal manufacturing processes of this type (e.g., variations of size and location of holes) and theoretically analyzed how these imperfections affect the performance of the photonic crystal.
The theoretical research of Emerson and the other researchers of EPUSP focused on the imperfections generated in the two main stages of the nanofabrication process normally used in photonic crystals such as the one studied: electron-beam lithography and plasma-assisted dry etching. “The results presented allow to assess that the electron-beam lithography process has greater effect on the performance of devices that explore the dispersion of electromagnetic radiation through the photonic crystal, such as prisms, optical switches and modulators”, says Emerson. “However, the quality of the dry etching process has a more profound impact on the characteristics of devices into which linear or exact defects are introduced in the periodic network of the photonic crystal to insert harmonic modes within the photonic band gap. In this case, the dry etching has to be extremely well controlled for manufacturing the devices where waveguides and resonant cavities are among its main elements”.
In addition to making headway in understanding the role of nanofabrication processes of photonic crystals in the performance of nanophotonic devices, the authors of the paper were able to define a method to design planar photonic crystals with core and cover in thin film dielectric materials. “The methodology includes determining the dielectric function of the material by the spectroscopic ellipsometry technique to analyze the dispersion effects of the materials, determining the geometrical parameters that maximize the photonic band gap and the analysis of the impacts caused by deviations introduced in the manufacturing process”, explains Emerson.
The research received financial support from the National Council for Scientific and Technological Development (CNPq) and from the Financier of Studies and Projects (Finep).
The authors of the article. From left to right, at the laboratory:.
2014 is a celebration year for one of the protagonist institutions of the history of Materials research in Brazil. The São Carlos Institute of Physics (IFSC), from University of São Paulo (USP), celebrates its 20th anniversary.
However, the origins of IFSC and its contributions to Brazilian Materials Science and Engineering date back to 60 years ago. “From its origins, IFSC had a central role in the development of Materials Science and Engineering, since Materials research was present with the pioneers of IFSC,” says Professor Antonio Carlos Hernandes, IFSC dean from 2010 to 2014 and researcher in the field of Materials.
The beginning of the history can be set in 1953, when USP, which had been founded in 1934, opened a teaching and research facility in the then small city of São Carlos, in the heart of the state of São Paulo. It was the School of Engineering of São Carlos (EESC), which exists to the present. At the time, the dean of the school, Theodoreto Souto, mandated to form a team of lecturers and researchers, recruited professors to São Carlos, mainly in São Paulo (USP), in Rio de Janeiro and abroad, but failed for them to settle in town for long.
From Rio de Janeiro, the first to integrate the EESC professors’ team was physicist Armando Dias Tavares, assistant of Joaquim da Costa Ribeiro in the Physics laboratories of the National School of Philosophy of the University of Rio de Janeiro (now Federal University of Rio de Janeiro, UFRJ). Then, collaborators and students of Dias Tavares, who had learned to do science in the “school” of Costa Ribeiro and Bernhard Gross (main pioneers of Materials research in Brazil) left the “marvelous city” to the inland of São Paulo, invited by Souto. Among them, the newly graduated in Physics and Chemistry and honeymooners Sergio Mascarenhas Oliveira and Yvonne Primerano Mascarenhas – a couple who leaved an important legacy in the history of Materials Science and Engineering in the region and in the country – arrived in São Carlos in 1956.
At a time when most of the human and material resources for research in Physics, in the world and in Brazil, were intended for Nuclear and High Energy Physics, the Mascarenhas couple chose to start studies in Condensed Matter Physics, field they had worked with Costa Ribeiro in Rio de Janeiro. Documents prepared by IFSC state that Sergio and Yvonne saw two possibilities in that area for the group of São Carlos: to internationally stand out in a field where there was less competition, and to generate applications that had a positive impact on the region’s economy and quality of life of its population.
Thus, in the 1960s, Sergio Mascarenhas created the Condensed Matter Physics Group. “Thanks to a very strong exchange between USP in Sao Carlos, and the universities of Princeton and Carnegie Mellon in the United States, and also groups from England and Germany, mainly in Stuttgart, we managed to establish a very intense research training program, which continues to this day”, Mascarenhas commented in an interview granted in 2013 to the SBPMat Newsletter. Among the works with the greatest impact conducted at the time by the São Carlos group, it is possible to mention research related to defects in crystals, such as ionic crystals with a color core, which were later used for optical memories.
In the late 1960s, a new teaching and research institution, the Federal University of São Carlos (USFCar), was created in town, with the effective participation of professors of the EESC group. In particular, Sergio Mascarenhas, who was the first dean (pro tempore) of the university, proposed the creation of the first graduate course in Materials Engineering in Latin America, seeking to build a bridge between Materials Science and the generation of products, processes and services. The course started its activities in 1970.
In another pioneering initiative in the Materials field, the São Carlos group, with Sergio Mascarenhas as head of the organization, hosted the Brazilian community of solid state physicists (then consisting of about 50 researchers) in town to conduct the “First National Symposium on Solid State Physics and Materials Science “in a small shed.
As a result of the growth, institutionalization and gain of autonomy trodden by Mascarenhas and colleagues of the São Carlos group, in 1971 the Institute of Physics and Chemistry of São Carlos (IFQSC) was created, and the first dean was Mascarenhas himself. IFQSC had from its very beginning a Department of Physics and Materials Science, and a Department of Chemistry and Molecular Physics. Another step was taken in 1994 when IFSC was dismembered, giving rise to the Institute of Chemistry of São Carlos (IQSC) and IFSC, whose first dean was Yvonne Primerano Mascarenhas.
Another milestone in the part of IFSC in the history of Materials research in Brazil was the creation, in 1993, of the inter-unit program in Materials Science and Engineering at USP São Carlos. Managed by IFSC, the program brings together professors of this Institute, IQSC and EESC, as well as researchers from other institutions in the region.
Action with academic and social impact
Besides participating in the inter-unit program, IFSC has one of the most acknowledged and applied postgraduate programs in Physics in the country, which has obtained, since its creation, full marks in assessments from the Federal Agency for the Support and Evaluation of Graduate Education (CAPES). Within its master’s and doctorate, it is possible to perform research in a wide range of topics, including several possibilities in the Materials field, from fundamental research in Condensed Matter Physics to studies on semiconductor materials, polymers, ceramics and glass. Also in the Materials field, IFSC currently has consolidated research groups, for example, the Polymer Group of “Professor Bernhard Gross,” and is home to large projects such as National Institutes of Science and Technology (INCTs) and Research, Innovation and Dissemination Centers.
However, the impact of academic performance of the São Carlos group in the Materials field has exceeded the limits of the city of São Carlos. According to Professor Antonio Carlos Hernandes, the first consequence of this performance was the graduation of doctors (PhD) who began to operate in such field in other higher education institutions. “Thus, many university and research centers operating in Materials today have the IFSC training on their DNA”, says Hernandez.
“IFSC brings together what is essential to the quality of Materials research, with equipment and people with experience in various types of materials,” says Professor Osvaldo Novais de Oliveira Junior, deputy dean of IFSC for the period 2012- 2016. Relying on these features, Novais adds, hundreds of masters and doctors graduated in Materials, many of which have become leaders of research groups in all regions of Brazil. “These leaders of various institutions, as well as others who are part of IFSC, currently play an important role in organizing the Materials community in the country, acting in the Brazilian Materials Research Society (SBPMat), coordinating events and national and international cooperation programs, and formulating public policies”, he adds.
But the impact of IFSC’s performance in the Materials field goes beyond the academic environment. Professor Hernandes highlights, among other examples, the creation of technology-based companies located in the city of São Carlos. “These high-tech companies originated from IFSC researchers work, often involving Materials research”, professor Novais states, which also brings up another type of social contribution made by professors and researchers of the institute, the “tireless work of popularization of science, with various programs for students of primary and secondary education, as well as for the general public. “
Luís Fernando da Silva is the winner of the 2014 award for best thesis in the field of Materials, granted by the Brazil´s Federal Agency for the Support and Evaluation of Graduate Education (CAPES). Luís Fernando´s Doctoral thesis, “Synthesis and characterization of SrTiO3 and SrTi1-xFexO3 compounds prepared by microwave-assisted hydrothermal method”, was defended in 2013 in the São Carlos School of Engineering at University of São Paulo (USP). The research was advised by Professor Valmor Roberto Mastelaro.
The result of the Capes Award 2014 was released in early October. The award ceremony will be held on December 10, 2014, in Brasília.
Read our interview with Luís Fernando.
SBPMat Newsletter: – Could you tell us briefly about how your interest in science started, and what were the most important moments in your academic career so far?
Luís Fernando da Silva: – My interest started during my undergraduate studies in Physics at the São Paulo State University (UNESP) at Bauru. I entered the research initiation program in my second year, and my project comprised the structural characterization of GaAs and GaN film, having Professor José Humberto Dias da Silva as my advisor, and receiving funds from the São Paulo Research Foundation (FAPESP). During my last undergraduate year, my work received an honorable mention in the USP research initiation symposium, which managed to motivate me further to enroll in a Master’s program in the field of Materials. Due to my interest in structural characterization, I started my Master’s studies at USP being advised by Professor Valmor R. Mastelaro, who is a reference nationwide in the field of X-ray absorption spectroscopy. My work consisted in preparing and characterizing amorphous and nanocrystalline StTiO3 and SrTi1-xFexO3 compounds. By the end of my Master’s studies, Professor Valmor Mastelaro proposed the challenge of synthesizing the SrTi1-xFexO3 compound using the hydrothermal-microwave method, considering that, up to that point, there was no record of its preparation by means of such method. After studying different parameters of its synthesis and characterizing the structural properties of the SrTiO3 compound, we started synthesizing the SrTi1-xFexO3, which we managed to do with great success. Both compounds were characterized using X-ray absorption spectroscopy (XANES and EXAFS) at the National Synchrotron Light Laboratory (LNLS), and the importance and originality of the results were accepted to be published by major journals in the field of materials: CrystEngComm (CrystEngComm, 2012,14, 4068-4073) and Physical Chemistry Chemical Physics (Phys. Chem. Chem. Phys., 2013,15, 12386-12393). In addition to that, according to the literature, the SrTi1-xFex03 compound has been successfully applied as a gar sensor, mainly for hydrocarbons and oxygen. Based on this application, Professor Valmor Mastelaro established a partnership with the microsensors group from Aix-Marseille University, in the city of Marseille, France. Thanks to said partnership, I received a scholarship to join the microsensors group for six months, counting with funds from the “Ciência Sem Fronteiras” (Science without borders) program. The results obtained were partially released by an important journal in the gas field, Sensors and Actuators B (Sens. Actuators, B, 2013, 181, 919–924). Currently in my Postdoctoral studies, I started a new research project, advised by Professor Elson Longo, in a partnership with Doctor Cauê Ribeiro from the instrumentation unit of the Brazilian Corporation of Agricultural Research (Embrapa), which comprises the study of photoactivated resistive gas sensors. Recently, I was granted a project to develop said research.
SBPMat Newsletter: – Why did you start to do research in the field of Materials?
Luís Fernando da Silva: – The field of Materials always fascinated me, since the time I spent in the research initiation program. The possibility of managing to synthesize a material, unveil its properties and use it for a technological application is challenging and fascinating at the same time.
SBPMat Newsletter: – In your opinion, what is the main contribution of your award-winning thesis?
Luís Fernando da Silva: – The main contribution of my thesis was the use of the x-ray absorption spectroscopy technique. The vast majority of existing articles in the literature report the method used to prepare the material and its application (gas sensor, photocatalysis, etc); however, there are only a few studies on its structural properties, restricted to the identification of the crystalline phases using the technique of x-ray diffraction. In my work, we could observe that materials (in my case, SrTiO3 and SrTi1-xFexO3) prepared using the hydrothermal-microwaves method, present substantial structural distortions. In addition to that, concerning the SrTi1-xFexO3 compound, we managed to analyze its detection properties against different gases (reductant and oxidant) in greater detail, since one of the most important parameters for a gas sensor is its selectivity.
SBPMat Newsletter: – What were the criteria that guided you to do a research recognized nationwide for its quality (the award-winning thesis)? To what factors do you attribute such achievement?
Luís Fernando da Silva: – Mainly my good relationship with the Doctoral advisor, Professor Valmor R. Mastelato, who gave me total freedom and credibility to develop this work, as well as important scientific contributions. Besides that, the infrastructure of the Center for the Development of Multifunctional Materials (CDMF/FAPESP) was crucial and allowed a proper and detailed characterization of the compounds studied in the thesis.
SBPMat Newsletter: – Would you like to leave a message for our readers who are doing research in undergraduate, master´s or doctoral level in the field of Materials?
Luís Fernando da Silva: – I believe that the main message is that before starting any research work (whether for initiation, master’s or doctoral studies), it is paramount for them to have pleasure doing their research and believe in the potential and quality of their work. If you believe the work you are developing has potential, you will seek your best to do it.